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Shaw Excavations Pty Ltd
EL 6/99 - Golden Ridge
Year 1 Annual Report
65 3001
Ken MorrisonDavid GarrardRussell Fulton
8 June 2000
653002
Figure 1 Location Map
APPENDIX l Resource Modelling Report
APPENDIX 2 The Dimension Stone Potential of the Hogans Road Diorite
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LIST OF CONTENTS
SUMMARY
TENEMENT INFORMATION
EXPLORATION PHILOSOPHY
PREVIOUS EXPLORATION AND MINING
YEAR 1 EXPLORATION RESULTS
YEAR 2 WORK PROGRAM AND BUDGET
REFERENCES
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TENEMENT INFORMAnON
EXPLORAnON PHILOSOPHY
This report documents all exploration completed up to 9 June 2000.
653003SUMMARY
EL 6/99 is a 30 km2 licence in the Golden Ridge area, NE Tasmania (Figure 1).
A ground magnetic survey and core drilling program wiD be the Year 2exploration priority.
Magnetic susceptibility measurements on cut boulders show the horoblendite tobe consistently more magnetic than other rock types within the Hogans RoadDiorite.
Previous exploration drilling around the Golden Ridge-Brilliant workings hasidentified a steeply plunging envelope of low grade gold mineralisation containingapproximately 25,000 ounces @ 1.6 - 1.9 glt (depending on the modelparameters) from surface to 300 metres vertical depth. The mineralisation hasbeen modelled to a confidence level sufficient for an Inferred Resource estimatebut the overall grade is too low on such a small resource. Mineralisation is openat depth and to the northeast and the distribution of higher grade intersectionsinside the envelope suggests there is reasonable potential, via infill andextensional drilling, to double the resource and delineate a higber grade deepzone beneath a low grade surficial oxide zone deposit.
Preliminary investigations into the potential for discovering a "black granite"dimension stone resource within the Hogans Road Diorite identified one facies - acoarse grained hornblendite - which exhibits the colour, texture and polishingproperties sufficient to justify an exploration program.
The licence was issued to Shaw Excavations Pty Ltd on 27 July 1999 for a 5 yearperiod, with the Year I anniversary due on 9 July 2000. Shaw Excavations hold 100%equity in the licence.
Access is via the all weather gravel forestry roads, Hogans Road and Granite KnobRoad, which link the South Esk Valley to the east coast towns of St Helens andScamander. An extensive network of forestry roads and vehicular tracks connect toHogans Road within the EL boundary.
Land Tenure is entirely State Forest (multiple use), with wood production andplantation establishment currently active over much of the licence area.
The ground is considered prospective for both gold and black granite dimension stoneand two separate exploration programs are in progress.
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Scale 1: 500ClQ (1 grid space =lkm)
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653004Devonian Diorite Intrusions
Contact Metamorphic Aureolein Mathinna Beds
IFigure 1 ISHAW EXCAVATIONS PTY LTD
EL 6/99 Golden RidgeLocation Map
(Geology from st Helens': 50000 sheet) Compiled: K.C.Morrlson I Drawn: A.Carroll I Dale: June 2000
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b5JOD5Gold
The principal aim is to thoroughly explore the ridges of contact metamorphosedMathinna Beds, from Golden Ridge to Risky Ridge, for resources of low grade(I -3 glt), non refractory gold mineralisation at shallow depth and high grade narrowvein reefs with underground mining potential.
On the basis of the results achieved by previous companies exploring Golden Ridge, atarget in the order of 30,000 to 60,000 oz gold in ground is realistic, and will benecessary to achieve viability. It is likely that the target tonnage will be contained in atleast two separate ore bodies.
Previous work by the Billiton Joint Venture and by MPI, together with earlierGeological Survey mapping on the 1: 50,000 St Helens sheet, demonstrates that the oldgold workings are located within a narrow (1000 to 1300 m wide) thermal aureolearound the margin of the Poimena Pluton. The aureole is expressed as a hornfels andcordierite/andalusite spotting facies in Mathinna Group sandstones. Magnetics andgravity signatures of the granite underlying the mineralised part of the aureole suggest acomposition distinct from both the Poimena adamellite and the Pyengana granodioritebut a genetic link between granite and gold has not been demonstrated (Davidson andRoach, 1990).
Two distinct styles of gold mineralisation exist at Golden Ridge (Dugdale, 1998).
1. discrete quartz veins, 0.5 - 1 metre wide, hosted either in granite or in MathinnaBeds au/side the hornfels aureole. Gold is associated with abundant sulphide,and geochemically anomalous arsenic and antimony zonation are characteristic.Mineralisation is confined to the veins (Trafalgar, Double Event, Queen of theEarth).
2. en echelon, steeply dipping narrow vein sets and cross cutting mineralisedfractures, hosted in folded, interbedded sandstones and siltstones, within thehornfels aureole. Gold occurs in quartz veinIets, on limonitic fractures and in adiffuse form through siltstone beds. This style is low in sulphides and is bestdefined by gold geochemistry (Golden Ridge, Brilliant, New Carthage).
Significant near surface mineralisation was intersected around the Brilliant Prospect, incosteans and percussion drill holes by the Bil1iton IV (Randall, 1991, 1992a and b) andin diamond drill holes by MPI (Dugdale, 1995, 1998; Frances, 1996; Masur, 1997).These results, particularly the southeasterly extent of mineralisation intersected byGRD-2 and --6, suggest potential for infill drilling in several fences to outline a resourceover a strike length of some 150 metres and a mining width of 20-50 metres. Thetarget therefore is in part analogous to the Fosterville deposits in central Victoria,which are currently worked as an open cut heap leach operation (Arne et. aI., 1998).
The Brilliant prospect is contained within a 10 ppb BLEG soil contour. Similaranomalies were identified by Billiton in the hornfels aureole at New Carthage, and byMPI at Risky Ridge.
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G5300C
Initial RC drilling on the New Carthage prospect was azimuthed east-west and did nothit significant mineralisation The distribution of old diggings and the impressive 20metres at 17 glt surface rock chip result achieved by the Billiton JV (Randall, 1992b)suggest that an east-west strike to the mineralistion is plausible and remains untested.
Further north in the hornfels aureole, at least two ridges with similar morphology toGolden Ridge remain essentially unexplored; the ridge east of Double Event(conceptual target based on a Trafalgar-New Carthage analogue - no exploration todate) and at Risky Ridge (32 ppb BLEG soil anomaly with no follow up to date).Reconnaissance rock chip and stream sediment sampling will evaluate both areas.
Clearly Brilliant is the most advanced prospect in the tenement and the proposedproject hinges on its viability. Its potential is enhanced if a central mill can beestablished at Mathinna, fed by several satellite mines in the district.
A second program is aimed at testing the Devonian diorites in the EL for their potentialin the high value "black granite" end of the dimension stone industry. A resource ofhigh quality dimension stone would have export potential and the initial exploration willdetermine if any portion of the Hogans Road Diorite is of sufficient quality and in alocation suitable for low cost quarrying. A means of discriminating between thevarious rock types within the diorite bodies is necessary to enable drill site targetting.If the initial investigations into the dimension stone geology are positive then thisprogram has the potential to become the exploration priority ofEL 6/99.
PREVIOUS EXPLORATION AND MINING
Small scale open pit and underground gold mining occurred at the now abandonedworkings marked on Figure I, between the late 1890s and the mid 1930s. Severalunpublished reports by W. H. Twelvetrees and Q. J. Henderson, archived in the MRTlibrary, describe these workings, most of which only produced small parcels of oregrade vein quartz for testing. The Brilliant workings were by far the largest, withferruginous sandstone as well as vein quartz mined from a small pit and limited shallowunderground stopes. Evidence of a mill and eroded tailings are still visible down slopefrom the Brilliant and Golden Ridge workings, extending to Brilliant Creek.
Randall (1991) briefly reviews the regional stream sediment surveys and limited soil androck chip sampling conducted over large tracts of NE Tasmania, including the GoldenRidge area, by Texins Development Pty Ltd and Union Corporation (Aust) Pty Ltdbetween 1980-1982. The Golden Ridge workings were also held under explorationlicence and mining leases by Oceana Tasmania, from 1982 to 1992 but little explorationwork appears to have been done.
The only significant modem gold exploration in the Golden Ridge area consists of twoprograms conducted between 1989 and 1998.
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YEAR I EXPLORATION RESULTS
• Re-establishment and survey control of grid.
• Petrography, geological interpretation of Bril1iant-Golden Ridge mineralisation.
G53007
MPI Gold Pty Ltd EL 12/93
Billiton Australia and Joint Venture partners; Aureole NL,American Horizon Resources Inc; Federation Resources NLEL58/88
1989-1992
• Extension of the Billiton stream sediment survey.
• 10 cored diamond drill holes (2125 m) under the Brilliant-Golden Ridge workings.
Billiton withdrew from the JV late in 1992 because they considered that the potentialwas too small for their objectives and no further work was done by the licencee group.
• Support for two Honours projects. 7 RC percussion drill holes (574 m) tested theBrilliant and Trafalgar-New Carthage prospects.
• Rock chip, stream sediment sampling, reconnaissance mapping and sampling ofworkings.
1993-1998
• Grid based mapping, BLEG soil survey, costeans, further stream sedimentsampling. Consultants studies on structural, geochemical and contact metamorphiccontrols on mineralisation.
Shaw Excavations Ply Ltd submitted a successful bid for ETA 495 in February 1999and EL 6/99 was subsequently granted in July 1999.
• Mapping, soil, rock chip survey.
MPI relinquished the EL in 1998, due to a perceived lack of size potential andcontinuity of mineralisation.
David Garrard hired the Surpac facility at Coffey Geosciences Ply Ltd, Hobart, andproduced the report shown in Appendix 1.
Mining Geolgist David Garrard, SVEDA Ply Ltd, was engaged to construct a Surpacmodel of the gold mineralisation intersected in drill holes and costeans in the GoldenRidge-Brilliant area, by the Billiton JV and MPI. MPI kindly provided, free of charge,digital files from their Perth database and their assistance and its consequent saving ofcost and time is gratefully acknowledged.
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G53008
Two block models were created, based on projected axial distances detennined fromsemi variograms. Both models use 10 metre strike dimension (strike = Grid North =060 AMG) and 10 metre vertical dimensions, with the difference being the two being 5metre versus 2 metre horizontal widths normal to strike (see Appendix I).
Both models show approximately 25,000 ounces at a cut off of I glt gold but the modelwith the tighter width dimension resulted in less dilution for the same contained gold.The average grade is 1.56 glt for the 5 metre wide blocks and 1.87 glt for the 2 metrewide blocks.
The distribution of grade in the vertical dimension, as indicated by both models, showsa relatively lower grade zone down to ISO metres below surface, then an abrupt changein trend to higher grade mineralisation, with peak grades at about 200 metres.
If the shape of the mineralisation envelope is roughly symmetrical, then extensionalsectional drilling to grid north has the potential to double the size of the envelope. It isalso likely that the average grade within the existing Inferred Resource would increaseif the same models were run on 20 metre sections, if infill drilling data were available.
Both outcomes will be necessary to generate a viable resource.
Black Granite
Consulting Geologist Russel Fulton reviewed the geology of the Hogans Road Diorite(Appendix 2) and produced cut hand specimens of various rock types encountered.Preliminary indications were that the lithology with most potential, on colour andtexture grounds, is a very coarse, olivine, pyroxene ± plagioclase hornblendeamphibolite.
Reconnaissance field investigations over the five "diorite" bodies revealed a diversity oftextures and mineralogy, with the best potential for discovering a resource of coarsehornblendite in a location suitable for low cost, low impact quarrying, being in thenorthern, and largest, diorite occurrence (Figure 1).
Seven subcrop boulders in the 0.25 - I tonne range, covering the range of rock typeswhich were identified visually, were collected from a 200 metre radius centered at586,900 E, 5,419,600 N. The boulders were cut and polished by Dunn MonumentalMasons Ply Ltd, Launceston. One rock type stood out in terms of its texture, colourand lustre under polish - the coarse grained hornblende amphibolite. The other grey,black and green coloured facies within the rock unit are cDnsidered tD have Dnlymarginal pDtential as dimensiDn stone (JDhn Dunn, pers cDmm).
Magnitic susceptibility measurements Dn the cut and pDlished faces Df the sevenbDulders shDw that the amphibolite has significantly higher magnetic susceptibility thanthe other rocks (Table 1) and therefDre ground magnetics is pDtentially an effectivemapping tDDI to generate drill targets.
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653009Table 1
Hogans Road DioriteMagnetic Susceptibility Readings (10.5 SI) - 2 March 2000
(all readings on cut andpolishedface afboulders approx. 0.25 - 1.00 tonne)
Boulder 1 Coarse Amphibolite (Black Granite)Range 1.73 - 2.46Mean 2.21n= 10
Boulder 2 Coarse Porphyritic Tonalite (Green Granite)Range 1.18 - 1.52Mean 1.34n = 10
Boulder 3 Medium Diorite (Grey Granite)Range 1.03 - 1.99Mean 1.42n = 11
Boulder 4 Coarse Porphyritic Tonalite (Green Granite)Range 1.05 - 1.56Mean 1.20n= 10
Boulder 5 Coarse Porphyritic Tonalite (Green Granite)Range I.00 - 1. 29Mean 1.17n= 13
Boulder 6 Medium Diorite (Grey Granite)Range 1.20 - 1.83Mean 1.49n = 10
Boulder 7 Coarse Porphyritic Tonalite (Green Granite)Range 1.56 - 1.86Mean 1.71n= 13
Expenditure
For the 8 month period, 1 August 1999 to 31 March 2000, a total of$25,932 was spenton gold and black granite exploration within EL 6/99
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YEAR 2 WORK PROGRAM AND BUDGET
Masur, G., 1996, Annual Report EL 12/93 - Scamander: TCR 97-4076.
Dugdale, J., 1995, Annual Technical Report EL 12/93 - Golden Ridge: TCR 95-3801.
$5,000.00$30,000.00$10,000.00$30,000.00$10,000.00$30,000.00$10,000.00
$125,000.00
The following Year 2 work program is itemised in order of priority.
REFERENCES
• Ground Magnetics Survey - Hogans Road Diorite northern body• Core drilling program on magnetic highs• Rock chip and stream sediment survey - Risky Ridge area• Test Pit - Hogans Road Diorite northern body• Accreditation, polishing tests• Percussion drilling program - Trafalgar-New Carthage• Compilation, drafting, reporting
Randall, J.P., 1992a, EL 58/88 Golden Ridge Joint Venture: Annual ExplorationReport for the period 7/4/91 to 7/4/92.
Randall, J.P., 1991, EL 58/88, Golden Ridge Joint Venture: Annual Exploration Reportfor the period 7/4/90 to 7/4/91.
Arne, D.C., Jijun, L., McKnight, S., Bierlein, F.P., Mernagh, T.P., and Jackson, T.,1998, New developments in understanding the Fosterville gold deposits,Victoria: VICMIN 98, ATG Bulletin 24.
Davidson, G., and Roach, M., 1990, The geology, geophysics and mineralisation of theGolden Ridge Area, Northeast Tasmania: Unpublished CODES report forBilliton Australia and Aureole Resources.
653010
The Company aims to spend $125,000 on black granite and gold exploration in year 2.Funding depends on a cash flow from the Kimbolton Coal Mine and if sufficient fundsare not available to achieve the Golden Ridge budget, then Shaw Excavationsundertake to partially relinquish EL 6/99 before the Year 2 anniversary, to reach aposition that can be adequately funded. If such a partial relinquishment becomesnecessary it would most probably be based on a separation of the gold and black graniteprojects.
Dugdale, J., 1998, Final Technical Report, EL 12/93 - Scamander River Prospect: TCR98-4223.
Frances, DJ., 1996, Annual Technical Report EL 12/93 - Scamander: TCR 96-3916.
Randall, J.P., 1992b, EL 58/88 Golden Ridge Joint Venture: Annual ExplorationReport for the period 7/4/92 to 7/4/93.
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00 4463A-Resource Modelling Report - EL6/99 - Brilliant _Golden Ridge Prospect - NE TasmaniaShaw Excavation Proprietary Limited~
Garrard. D.J. EL6/1999
653011
APPENDIX 1
Resource Modelling Report
Resource Modelling ReportExploration License EL 6/99
Brilliant - Golden Ridge ProspectNortheast Tasmania
00 4463A-Resource Modelling Report· EL6199 • Brilliant ".Golden Ridge Prospect· NE TasmaniaShaw Excavabon Proprietary Umited-
Garrard. D.J. EL6/1999
.1 - 999
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•.OJ - .3.0 -.01
Undefined
TeDement Holder:Author:Date:
Shaw Excavation. Ply Ltd.Dave Garrard27 January 2000
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Table 1:
Table 2:
Table 3:
Figure 1:
Figure 2:
Figure 3:
Figure 4:
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Figure 6:
Figure 7:
Figure 8:
Figure 9:
653015
CONTENTS
INTRODUCTION
SCOPE OF WORK
SOURCE DATA
MODELLING
RESULTS
CONCLUSIONS AND RECOMMENDATIONS
REFERENCES
TABLES
Material contained in mineralised envelope at various grade cutoffs.
Material contained in mineralised envelope at various northings.
Material contained in mineralised envelope at various depths.
FIGURES
Location Plan
Plan view showing transformed grid.
Section view showing interpreted mineralisation @ BOmN.
Cross Section @ 40mN
Cross Section @ BOmN
Cross Section @ 120mN
Cross Section @ 160mN
Cross Section @ 200mN
Oblique view of terrain and block model.
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653016SUMMARY
This report details resource modelling activities undertaken on behalf of ShawExcavations Pty Ltd. on the Brilliant - Golden Ridge Prospect within EL 6/99, in a 3week period during January 2000.
An Inferred Mineral Resource of between 400,000 and 500,000 tonnes at a grade ofbetween 1.6 and \.9 glt of gold is estimated to exist at the prospect as currentlydefined by the data.
The author of this report is a member of the Australian Institute of Geoscientists andis considered a "Competent Person" under the JORe code for the purpose ofestimating Mineral Resources in narrow vein type gold mineralisation.
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653017
1. Introduction:
This report details resource modelling work done on behalf of Shaw Excavations PtyLtd. (Shaw) on gold mineralisation at the Brilliant - Golden Ridge Prospect within EL6/99. The tenement is currently in license year I.
The work was carried out using information gained entirely from the BillitonAustralia joint venture (Billiton) and MPI Gold Pty Ltd. (MPI), both who held andexplored the ground between April 1989 and October 1998. Billiton undertook streamsediment sampling, soil sampling, mapping and rock chip sampling, as well asdigging 6 costeans and drilling 4 RC holes over the prospect. MPI continued fromNovember 1993 with more detailed mapping and drilled 10 diamond drill holes ontransform sections approximately 40m apart.
Both companies intersected significant gold mineralisation (> Ig/t) associated withquartz veinlets and ferruginous fractures in a folded and homfelsed silt-sandstonesequence. The envelope of gold mineralisation appears to be striking ENE anddipping steeply East and is intersected by late stage brittle faulting striking NNE (allbearings on AMG). This is interpreted to give rise to an en-echelon arrangement ofmineralised pods within the envelope, increasing with depth to the SE.
2. Scope of Work:
No new information has been gathered since the work done by Billiton and MPI andthis exercise was aimed purely at collation and 3 dimensional resource modelling. Itwas hoped this would shed some light on the nature of the gold mineralisation, itsextent as currently defined and targets for further exploration.
As such only assay data relating to in-situ mineralisation was used i.e. from thecosteans and drilling. An attempt was made to link anomalous gold values to broadscale geology but this proved futile from the reports and is likely to require remapping and re-logging by a single geologist. Finally, no attempt was made to modelother trace element data as this information is incomplete and exists only for the 10diamond drill holes.
3. Data:
The data utilised was obtained from the annual Billiton and MPI reports held at theMineral Resources of Tasmania library - see references for a complete list.Digital data was also obtained from MPI to prevent re-entering, although this was notentirely complete and still required some input and validation from the text.
Of greatest interest was the gold assay data for the 6 costeans (Cos. I ;2 ;2A ;3 ;4 ;5and 10), the 4 RC holes (RCGR I to 4) and 10 diamond drill holes (GRD I to 10).The costeans were sampled at mainly 2m intervals and analysed for gold by fireassay. The RC and diamond drill holes were also completely sampled at regular 1mintervals (with the exception of GRD I and GRD 10 where certain sections were not
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653018
sampled) and analysed for gold by fire assay. For consistency, only the initial assay ofeach sample was used in the modelling.
Topographic data was obtained in digital format from MPI as were the surfacepositions of major features such as the access road, Brilliant Creek, costeans andhistorical workings. Collar positions, downhole surveys and geological logs for thedrilling were also obtained and validated against the text.
4. Modelling:
All 3D modelling was carried out using Surpac 2000 software in conjunction withExcel for editing the data.
A database was constructed in Surpac in which all the gold assay and geological logswere stored from the drilling. Extensions to GRD 2 and 3 (viz. GRD 2A and 3A) wereadded to the original logs instead of being treated separately and the costeans weretreated as horizontal drillholes for the purpose of modelling.
For the most effective construction of a model, the data was then transformed fromAMG co-ordinates to a grid orthogonal to the majority of the data and indeed the mostobvious strike of the mineralisation. This involved rotating +600 from AMG Northand making the origin of the new grid correspond to AMG 541 5600N and 585700E.
E-W Cross sections were then created from the transformed database at 20m intervals(+/- 10m) from the baseline at OmN on the new grid. An attempt was then made todefine continuous zones of gold mineralisation between the assays on section andbetween sections, using cutoffs of O.3g1t and 19lt respectively. This proved extremelydifficult on all but section 80mN, which has the greatest amount of data (6 diamonddrill holes).
The interpretation on section 80mN seems to indicate 7 to g discrete zones of>Igltgold mineralisation. These are up to 5m in true width and lie within zones of >O.3g1tmaterial which are up to 20m in true width. These zones dip steeply Eastwards (-85°)and seem continuous for 50 to 100 metres down dip. They also seem to lie in astaggered (en-echelon) arrangement, which deepens to the East. See figure 3.
A lack of consistency between the geological logs did not allow a firmerinterpretation than this although a vertical projection of the shear zones from surfacemapping would seem to contain the mineralised pods to some extent. Relating suchdiscontinuous pods between the sections 40m either side however proved futile due toa lack of information and instead an envelope was created which contained all thesignificant intersections along strike and with depth. This coincides rougWy with the0.3glt Au cutoff but does contain lower grade material due to the en-echelon nature ofthe mineralisation. Note that this also excludes a small amount of higher gradematerial where this did not seem consistent with the main style of mineralisation. Themost obvious example of this is that intersected by GRD 5 and 9 on the section at40mN, which seems to have a very limited vertical extent as shown by the low gradesin drilling immediately above and below.
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653019
To gain some idea of a reasonable distance for projection of this cnvelope beyond thedata, omnidirectional variograms were constructed trom all the assay data. Only thevariogram at _90 0 showed any reasonable structure and gave a range of -40m. Thiswas takcn as the maximum distance the data could reasonably be projected down dipand the envelope was constructed accordingly. A distance of 20m was used to extendthe envelope either side of the northern and southernmost sections where data existed(viz. 40mN and 200mN respectively). This resulted in an envelope 200m along strikefrom 20mN to 220mN, -60m across strike and over 300m below surface.
The final step involved creating a block model to aid the interpretation of gradedistribution within the envelope and to gain some idea of the contained metal abovevarious grade cutoffs. Two models were created for comparison, the first (Model I)using blocks of the dimensions 10m along strike (N-S), 10m vertically and 5m acrossstrike (E-W). Smaller blocks than this would not be realistic along strike and withdepth due to the scarcity of information but Model 2 used 2m wide blocks acrossstrike in an attempt to reflect the thin nature of the higher grade mineralisation.
The assay data was then composited at I m intervals to ensure consistent sample sizeand zones of no sampling were given a background value of O.OOlgit Au. Thecomposited data was then used to fill the models using both an inverse distancesquared (ID2) algorithm and Ordinary Kriging, both with an anisotropic search ellipsehaving the dimensions 40m downdip (_85°/150°); 20m along strike (0°/000 0
) and 10macross strike (0°/0900
). The interpolation was constrained to blocks within theenvelope but allowed data from outside to be used in the allocation of grade.
Results of this are shown visually in figures 4 to 9 and numerically by tables 1 to 3.
The following assumptions were made during modelling:• A specific gravity of 2.5 was used throughout, based on no measurements but
considered reasonable for the host rocks.• No top or bottom cuts were applied to the data.• No assumptions were made regarding possible mining methods.• Me!'llllurgical amenability was not taken into account.
5. Results:
Table 1 shows that both models give a very similar result in terms of contained goldabove a cutoff of 1.0 glt (approximately 25,000 ounces).
The difference is that the 2m wide blocks of Model 2 allow a tighter constraint of thisstyle of mineralisation which results in less dilution, giving higher grades at lowertonnes for a similar amount of contained metal. This is more realistic given individualassays in some zones but a final model should ensure that the block width is no lessthan the minimum stoping width to reflect the achievable grade.
Tables 2 and 3 report the material above 0.3 glt and 1.0 glt cutoffs for both models todemonstrate the currently defined extent of significant mineralisation.
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653020
Table 2 shows that 80% of the contained ounces occur within the first 100m of strikclength (sections 20mN to l20mN). This is due to a lack of information further northas there is no drilling deeper than 75m below surface between 120mN and 220mN.
Table 3 shows that the contained ounces are more evenly spread with depth althoughthe grade jumps significantly at around 200m below surface. Closer inspection of theraw data on sections 40mN to 120mN shows seven assays in excess of lO glt Au atthis depth and only one assay of 10 glt close to surface.
6. Conclusions and Recommendations:
Significant gold mineralisation exists at the Brilliant Prospect and it remains openalong strike and with depth. From the currently available information however, anestimate of25,000 ounces can be assumed to exist above a cutoff grade of 1.0 glt Au.
Depending on the method of extraction, this is likely to come from an InferredResource of between 400,000 and 500,000 tonnes at a grade of between 1.6 and 1.9glt Au. An Inferred category was chosen as it is defined by the Joint Ore ReservesCommittee (JORC) code to apply to situations where "the data is insufficient to allowthe geological and/or grade continuity to be confidently interpreted".
Note that this estimate should not be taken as achievable as no mining or economicconstraints have been applied, nor should they be until enough data has been gatheredto allow classification into an Indicated or Measured category. In order to do this thefollowing programme ofwork is recommended to be carried out:
• Re-Iogging of available core with an emphasis on identifYing structuralfeatutes between sections and surface mapping.
• Exploration diamond drilling at 40m spacings along strike beginning onsection 160mN. Figure 7 shows a proposed layout of 5 holes between 200 and300m each and is also applicable for other sections where such holes do notalready exist. The holes should be drilled in the order shown with the finaldesign and decision to drill each hole being decided on the results and path ofthe previous one.
• Infill diamond drilling at 20m sections with a similar layout to that shown infigure 7. This should enable more confident interpretation of geology andgrade continuity along strike.
Dave rardGeological Consultant
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6530218. References:
Randell, JP. 1991 - Billiton Australia. EL 58/88 Golden Ridge Joint Venture.Annual exploration report for the period 7 April 1990 to 7 April 1991.
Randell, JP. 1992 - Billiton Australia. EL 58/88 Golden Ridge Joint Venture.Annual exploration report for the period 7 April 1992 to 7 December 1992.
Dugdale, L.J 1995 - MPI Gold Pty Ltd. EL 12/93 Golden Ridge. Armual TechnicalReport for period ending 12 November 1995.
Frances, D.1. 1996 - MPI Gold Ply Ltd. EL 12/93 Scamander River Project. AnnualTechnical Report for period ending I October 1996
Masur, G. 1997 - MPI Gold Pty Ltd. EL 12/93 Scamander River Project. ArmualTechnical Report for period ending 12 October 1997.
Dugdale, L.1. 1998 - MPI Gold Pty Ltd. EL 12/93 Scamander River Project. FinalTechnical Report for period ending 12 November 1998.
Australasian Code for the Reporting of Mineral Resources and Ore Reserves (JORCCode - 1999 edition)
Table 1:
a.
G53022
MArial ContI!!ntd In MlntrallHd Emlopt at "'rlou! Grade CutofJ!:
10m x 10m x 5m bIoclul tilled by 102
Grade Range Volu_ T_ A... GnlcIe e-Ined
VI"" m3 -0-2.5 VI"" -""O.lHl.Ol 1,623,500 4,058,750 0.00 00.01·0.3 934,250 2,335,625 0.13 9,7620.3-1.0 690,625 1,726,563 0.57 31,8071 0-20 175,563 438,906 133 18,78220-50 25,125 62,813 2.74 5,5295.0-10.0 2,500 6,250 5.69 1,143
>10.0 0 0 0.00 0orana Total I :I,4lI1.lIAI8.UlI._1 U~ 87.UZ4
Blocks> 1.0 g/t AuTonnes Ave Grade ContainedSQ '" 2.5 ¢ Au ounces Au
507,969 1.56 25,454
b. 10m x 10m x 2m bIoclul tilled by OnIln11ry Kriging
Grade Range Volu_ T_ A.., Grade e-InedVI"" m3 OIl' 2.5 VI"" -""
O.lHl.Ol 1993400 4983500 0.00 00.01·0.3 817 400 2043500 0.13 85410.3-1.0 488800 1222000 0.55 217261.0-2.0 126,200 315,500 1.34 13,562
2.0-5.0 33800 84,500 2.82 76505.0-10.0 4,600 11,500 6.59 2,437
>10.0 1,000 2,500 15.84 1,257Grand Total 3,.415,200 ....3.000 0.20 ",173
Blocks> 1.0 g/t AuTonnes Ave. Grade Contained59 =- 2 5 golf Au ounces Au
414,000 1.87 24,906
Table 2:
65302J
-inti G_-"y ""11M
0,3-1,020-.0 :> 1.0
SubT_0.3-1.0
.a-80 :> 1.0SubT_
0.3-1,080-80 :> 1.0
SubT_0.3-1,0
80-100 :> 1.0SubT_
0,3-1.0100 -120 :> 1.0
SubT_0,3-1,0
120 -1.a :> 1.0_T_
0.3-1,01.a -180 :> 1.0
_T_0,3-1.0
180 -180 :> 1.0SubT_
0,3-1.0180-200 :> 1.0
SubT_0.3-1,0
200 - 220 :> 1.0_T__T_
1/ll1t It 1/ll1t It lIlot__W ID2
Ton_ A__ c-..Cu_
.-2.5 ""11M _11M "2~,0ll3 0,62 .,957.2,500 1,53 2,091
2lI1lll13 0.75 7_ 12%299.063 0,61 5.61753,750 1.71 2.952
3&2,113 o.n 1 Tea 28%307.500 0,53 5,28090,313 2.09 6,060
311.813 0'" 11,311 Q%
210,625 0.56 5,27089,211 1.53 .,389mi...... 0.71 I_ ""'183,~ o,s. 3,20210.,531 1,26 .,21521fT_ 0.11 7:- 77%152,031 O.s. 2,!l44.e,25O 1.16
~1l1Ul11 0.11 -2.,!l44 O.~ 389211,250 1.7. 1,.7011.- 1.13 1.110 ....35,313 O..e s.315,625 1.S. n1lO.ll3lI 0.80 1,313 11%106,* 0.50 2,009211,250 1,26 1,063132.344 0.73 301t -78,5904 0.67 1,813
~1..e 6210.71 2. 13 1_0.80 67.
1/ll1t It 1/ll1t It 2lot__w~Ton_ Ave. Gmde ContlIIned Cumulllllve.,·2.5 ""... _11M "1.5,500 0,56 2,61523,500 2,09 1,581111000 o.n "111 I'JIo217,500 0.55 3.839~,500 1,11
~2IfT,OOO 0.80 2A'JIo226,500 O,s. 3,10387,000 2..e 6.681
313,100 1.07 10768 Q%
226,500 0.57 .,15683,500 1.92 5,1.1
312.000 0.13 1:- 17'JIo136,000 0.80 2,61076,000 U7 3,565
21iooo 0.11 8,1. -106,500 0,61 2,075211,000 1.38 1,152
13iaoo 0.71 3m fS7'JIo2.,500 0,51 .a121,000 1.90 1,262"-100 1.18 1_ 11%211,500 0.53 .5211,500 1.78 65138,000 0.90 1,103 -70,000 0.•0 1,1032.,500 1.38
~klOO 0.72 -.a,500 0,.3 55511,500 1,~ .95
~0.83
~1_
0...
Contained Gold with Northing
8,000(_ 1,0 gil cuIolI)
... ::::. . -::
7,000._..
o Model 1::I 6,000 • Model 24( 5,000: 4,000Co)c 3,000::I0 2,000
1,000a~ 0> e§> ~ ~ ~ 0> ~ ~ ~, , , .... '" '" cv
~ ~ 0> , , , , , , ,e§> ~ ~ ~ 0> ~ ~.... '" '"
Northing
653024
Tablll3: """" ConlIIIIIC! In .1""'*'1 Enw!opII1 yarlout D!p!!lIj
IlepIII O_Ranee, .....Surloce 0.3-1.0
to > 1.0500mRL _T_
0.3-1.0500 -450 :> 1.0
_T_0.3-1.0
450 -400 :> 1.0_T_
0.3-1.0400 - 350 :> 1.0
SubT_0.3-1.0
350 - 300 > 1.0SubT_
0.3-1.0300 -250 :> 1.0
_T_0.3-1.0
250 -200 > 1.0_T_...-T_
ffJlol x fGllt x &oJ _ _ Iw mTon_ A..._~cu_"·2.5 ..... _..
"179,688 0.56 3,2~1
98,906 1.39 ~,420
mi.... 0.- 7eaT 13%301,_ 0.57 5,_73,125 US
~374,IU 0.7~ 2lIl'484,375 0.59 9~
81,250 1.27 3,307lI8U25 0.• 12.111 51'"~21.25O 0,57 7,7!Y872,500 1,21 2,823
4113 750 0.88 10Ml -111,875 0.56 2,018
:z.~2.34
~1.38 -145,825 0.51 2,39755,938 1.51 2,721
201,883 0.711 1,120 ""'"82,188 0.85 1,72535,825 1.72 1,987
i;ig:1 0.-~
1_0.80
10nt x 10.. X 2m~ ...... ".....,.,Ton_ A.... _ eon_ Cum_..-2,5 ..... _..
"180,000 0.80 3,08890,500 1.~ ~,318
250,500 0.12 7:.e 18'1'210,000 O.~ 3,_87,000 1.~ 3,322m,ooo 0.71 8* 31'"330,000 O.~ 5,70873,500 1.55 3,870«13.500 0.72 U71l 51'"298,000 0.58 5,33957,000 1.57 2,872353,000 0.72 S,217 -90,000 0.55 1,591
1~~3.06 8,393
1 000 1.80 7983 -93,500 0.52 1,55133,000 2.39 2,538
128,500 1.01 ....., ""'"~2,500 0.59 81028,000 1.98 -ii-70500 1.15
,_11,' 0.81
Gold Grade with DeRth(above 1.0 gil adofl)
3.5 " "
3
2.5
~ 2~
~ 1.5
"1
0.5-
0 . -._,", ...
Surface -50 -100 o.lfjlh -200 -250 -300
01 02
i G5 39,,2~
MOUNT ,& " J'f.C~'~ c'<
~-
" --\Q
:\,
---I,
c-~-- -
·190
989/
"l20
Ir,ansir-;F~I~ -
:--10 :--rI
0"'.'"' <;~,,-_,_
--~$ J,/
">'~ !"-' ,
<
'. !:.'/lnJ
'. AI''''"i
I
1""""1)'_ 88 89 91 91 95 96
FlNGALlIkm ST M4RYS21km
Location of EL 6/99
BRILLIANT - GOLDEN RIDGE
Date- 28 January 2000T
145"
43"
Figure 1.
PRODUC[D by 'h~ Mapping Divllion. ll"dl D~plrtmfnL Ho~~rt.19aJHOMENCLATURE: hpoglllpnit Dimes an lhj~ mlp h~vl been ilp~~"ed by lhe "'orne~c1alu",Iiolrdal T"",,~jt
MAl ACCURJ.(Y, T~ ,vt,,~r lCtUlicr Df lIIi, m'~ i, ~ 25 m,lItl in rll, IIo/ilCM,1 p~lirio9uf ..ell drlin8il de"illnd ~ 5 mellel in !leVlliQ~
MAP RWABILlTY:Topographi~ inlonTIatioll luDjecled \0 limIted uPdate June I9tlJPUBlfC AIGl/rOF WAY ROlda Dr lrUk, D~ Ihil mlp dD nor n!teuarily lndl,ate ~ pUbli,fig~I~lw'r_
CQRRfCIIDNS To lu;"r;" rOfJr[li~g 'Ulur! I~);MJ DJ !~;J m.p. V'~/& ~~jj~g mOIJ ~ndOOIiqigtllltr in"';lec! to wri,~ III Ihl Direall(t/ M.ppina GPO B... 44A.l1ohart. TlISPnani .. 7001
UNIVERSAl GRID REFERENCEBEFORE GIVING A GRID REFERENCE, CIVILIAN USERSSHOULD-STAff TIfE NUMBER AND NAME OF THIS MAP
8515 GEORGES BAY
IIIIII
•
653026
~oo
'"
~CDoo
'"
\Projected
5415500N
_ Ir54:..::15=4.::.:oo::.:.N-------------t-~-~if---:)("T~---___1t:ct------C\----___=::i_-~S~U'!:R~P'!.A~C~S~O~F~T...!W~A::R~E=__.:I~N~T~L=_____..jQ BRILLIANT - GOLDEN RIDGEu
~ U1 U1 PLAN VIEW ON AMGI m m
:::: ~ 0'" SHOWING TRANSFORMED GRIDL g 0
.. '" '" Scale: 1: 1000 Figure 2 Date: 28-Jan-OO
~ SURPAC2000 - SURPAC Softw.re Intern.tiona)Scm
Ill: brll...Jlac.pf
".;
SOOEl
woo
'"
Scm
SURPAC SOFTWARE INTL
,..
'"oo'"
0 0.3 - 1.0 oft Au s-I
0 > 1.0 gft Au 'b
/ Projected Shear
300fl 300fl
BRILLIANT - GOLDEN RIDGEX/SEC ~ BOmN
::;;------------------- '--+-'~---------1_--:.I~n~t.:e~r~p~r~e~t~e;d~~A~u~M~i~n~e~r~a.:l.:i.:S~a~t:.:l~·o::n~__-jo 0
'" '" Scale: 1: 1000 Fig ur e 3 Date: 28-Jan-00
400fl 400fl
~
Ul 0
i ~•n~ooI
Ul
~•ng'~..~......:>.....,:>....~
o:>..~
~ brllJlhp.pf
Gl 6'~
500El 'iI". ".~ I ... """" 3~"~H" I 500ElI--------~...,~... "'. -. - .....•• .-.---+---------------jl- 'l.~".. ..... L llS.Q!>'-'-" -J~ _
~~~"" ---------------. ~.,~ .~~ ".~
~,.n:8ooI
'"~,.n
'"o~...~.,..
~
oom
'"oom
I-
n~- .;,~
1'-4_00_E_l --+ .,._6_~"....:..;,.•..-l~~~_J_=tof'_J_J-"'~~..._4_+_+_++_---------40-0-E_jl
" -~ '\XJ I~
<;~6'... .r6'~'-"o+-+-H#~\p.'.-....I-+-t-I-+-t-I-+-t-I-+--'-'-I
~:~-.,.' , ·li... ,+++++-+-+-...L...+-....-+1
BRILLIANT - GOLDEN RIDGEX/Sec @ 40mN on trans. grid
200El1-----------+g:-----------------~--...:1~O~X:..:1~O~x~5~m~b~1~0~C~k:.:S~f~i~1~1~e~d~b~Y~I::D~2~-__.j
m Scale: 1: 1000 IF i g ur e 4 Date: 28-Jan-00
300El
D 0 - 0.01 g/t Au
D 0.01 - 0.3 g/t Au
D 0.3 - 1.0 g/t Au
[] > 1.0 g/t Au
/ Projected sne.r
L
L
L
LSURPAC SOFTWARE INTL
300El
O":JCJlWol\J00
Scm~I
~ brilJlhn.pf
~
'" 0c: 0D m..,•nl\l000
'"c:D..,•n'"0-.. 500ElxCO.,CD...:>.....,:>CO..-0:>CO...
400El
300El
l\loom
g:om
500El
400El
300El
DDoo/
o - 0.01 g/t Au
0.01 - 0.3 gft Au
0.3 - 1.0 g/t Au
> 1.0 !jilt Au
PrOjected Shear
SUR PAC SOFTWARE INTLBRILLIANT - GOLDEN RIDGE
X/Sec ~ BOmN on trans. grid;;;----------------- !--+~!-------I---1::0::X~1::0::x~5~m~b~1~o~C~k:.:S~f~i~1~1~e~d~b~Y~I:.:D~2~-~o 0m m Scale: 1: 1000 Fig ur e 5 Date: 27-Jan-00
Scm
~ brllJlhq.pf
InCD"tJ,.nI\Jooo
InCD"tJ,.nIno~
".X....,......:>".....,:>..".-o:>..~
oo'"
500EI
I\Joo
'"
\.~, (,;0 3 •.•.•.•.~.~ M... T -47.00
\\:'- I: ·.1·.
h
woo
'"
I~~ 500EI
~
400EI
300EI
oooo/
o - 0.01 g/t Iw
0.01 - 0.3 g/t AU
0.3 - 1.0 g/t Au
> 1 0 g/t AU
PrOjectea Snear
Ll
1L
1L
L
300EI
I-
L
L,L-L.--.l ----'-- .,--II
SURPAC SOFTWARE INTL ~CJl
BRILLIANT - GOLDEN RIDGE ~
X/Sec @ 120mN on trans. grid ~
g:--------------------~g--------t_--.:1~O:!.:X~10::x~5~m,..gb;1::.0.:C~k~S~f~i:.:l;1~e~d~b~Y~:.ID~2--__.jC>
'" '" Scale: 1: 1000 IF i 9 ur e 6 ~ Oate: 28~J8n-00
5cm
Ill: bril..Jlhu.pf
~">n'"ooo
'"CD
">n'"o~..~...,'"H
"..'".,"....~
o
"..-
- '" w0 0 00 0 0
'" '" '"16 I .\ra\ ~~~'i9Olt
16~\I~·~ .Q
tJ"" "11.... ":.':
;...........
~i~ ~500El 16 :::::-....... ",
l 500El'" .::: ",
-0
~.'" ' ..I· ....
[ ~
~•I> '''~
.rJ if....
~''b
":'b
1--1--Suggested layou for fr" 11 ing
I-- I--
1--1-- I--
I--
hole 1
VVV
t- t- /400El ./ 400El
v V V17
VI t-
hole .4 /V V1/
/LL
1 t-
L
Vhole 21
/300El / 300El
L
/D o - 0.01 g/t Au L
D 0.01 - 0.3 gft Au /
0 0.3 - 1.0 gft Au
EJ > 1.0 gft Au -
/hole 5
LProjected Shear
L
J SURPAC SOFTWARE INTLBRILLIANT - GOLDEN RIDGE
hole 3 X/Sec IS! 160mN on trans. grid- '" 10x10x5m blocks filled by 1020 00 0
1000 IFig ur e 7 ~ Date: 2B-Jan-00'" '" Scale: 1:
5cm
~ bril---<lhv.pf
'"~•nlUooo
-oo'"
400El
300El
D 0 - 0.01 v/t Au
D 0.01 - 0.3 v/t Au
D 0.3 - 1.0 v/t Au
D > 1.0 glt Au
/ Prolecteo Sne.r
Ll
LL
1
:go
'"
L
L
I-
I-L
n
~
woo
'"
400El
l
I-
300El
I-
L
[,L-L.--.L -'-- --'j
SURPAC SOFTWARE INTL
Scale: 1: 1000 IF i 9 ur e 81 Date: 28-Jan-00
BRILLIANT - GOLDEN RIDGEX/Sec @ 200mN on trans. grid
10x10x5m blocks filled by 102oo
'"oo
'"
,.. Scm
------ 653033
Date: 28 Januarv 2000Fi2ure 9.
BRILLIANT - GOLDEN RIDGEOblique View of Terrain and Block Model
Blocks coloured by gold graden
f)__ t")--4------
---t----.j....,l.~~
--.--t----+---+-----l-7L--
-'AoI] ~-----t-----~
SOD
:~5 I] Z--
-- ---Block Colour Key:
-3Jl1] 70.0 - 0.01 glt Au •./...
-- •-- --- 0.01 - 0.3 glt Au--
?51J Z 0.3 - 1.0 g/t Au D-- •-- -- > 1.0 glt Au
--::'11 II Z-- -- --
--
~I] Z__
IIIIIIIIIIIIIIIIIIII
•
00 44638-The Dimension Stone Potential of the Hogans RoadDiorite - EL 6/99
Russell Fulton Pty Ltd; Shaw Excavation Proprietary LiFulton, R EL6I1999
653034
APPENDIX 2
The Dimension Stone Potentialof the Hogans Road Diorite
The Dimension Stone Potential of the Hogans RoadDiorite - EL 6/99Russell Fulton Pty Ltd; Shaw Excavation Proprietary Li
Fulton, R. EL6/1999
00 44638IIIIIIIIIIIIIIIIIIII•
-
TIIE DIMENSION STONE POTENTIAL OF
TIIE HOGANS ROAD DIORITE
Russell Fulton Ply. Ltd,PO Box 81
BRIDPORT 7262
65 3035
IIIIIIIIIIIIIIIIIIII
•
IlMndl F.".. P(F. LId. ACN 01$ OZ4 JlJ
653036INTRODUCTION
The Hogans Road diorite (HRD) is a suite of igneous rocks with very diverse
compositions, which include very unusual types such as olivine-pyroxene hornblendite and
biotite hornblendire, as wen as more conunon types such as diorite, quartz diorite, and tonalite.
Of these types, the hornblendites contain a very large proportion of the hard black
mineral hornblende and this gives the rock a dark green-black colour which on a polished
surface is potentially quite attractive. In terms of the dimension stone industry, the HRD would
be classified and marketed as a ~black granite". Within the dimension stone industry, the term
black granite includes many types of igneous and metamorphic rock types, the vast majority of
which are not granites in the strict geological sense.
Black granites fetch prices far in excess of those obtained for typical red grey and red
granites, such as the Cole Bay red granite or the grey granites obtained from the Scottsdale
Batholith in north-east Tasmania. Blocks of typical Australian granites fetch prices 0[$400 to
$1200 per mJ landed in Melbourne. Of the exotic black granites however, Blue Pearl and
Emerald Pearl, both from Norway, bring $4000 mJ, and hnpaIa Black and Black Absolute,
both from South Africa, bring $3800 and $3500 mJ respectively, landed in Melbourne. The
hornblendites of the Hogans Road suite, if found to be suitable for extraction, would potentially
be marketable in this premium end of the market, competing against imported material.
At the global level, turnover in the world dimension stone industry is substantial, having
been estimated at around US$12-13 billion in 1995, on production ofaround 40 million tonnes.
Production has grown at 5-6% per armum over the long term. Australia has traditionally been a
very small producer of dimension stone, with production ofabout 132,000 tonnes or 0.3% of
world production in 1995/96.
In 1994/95, Australia exported 18,434 tonnes of stone, valued at about $7.9 million.
This was made up of crnde stone exports totalling 7,993 tonnes, valued at $3.254 million, and
manufactured stone exports totalling 10,441 tonnes, valued at $4.687 million. During the same
period, Australia imported stone to the value of $54.956 million which was comprised of crude
stone valued at $7.129 million and manufactured stone valued at $47.827 million.
Granite imports totalled $22.774 million or about 41% of the total value of stone
imports, and of this total, non-manufactured articles totalled about $9 million. Non
manufactured articles include crude or roughly trinuned granite, granite cut into blocks or slabs,
1
or cut or sawn granite. In contrast, non manufactured granite represented 96% of the $4.237
million value of granite exports for thaI period.
The importance of granite within the world dimension stone indusby has grown
substantially over the past few decades, from 19% of world production in 1976 to about 40%
in 1995.
Much of the above has been summarised from "Dimension stone in Victoria",
Geological Swvey of Victoria Report 112 (1997) by RL. King and K.S. Weston. This is an
excellent general reference book on the dimension stone indusby in Victoria and Australia and
contains many coiOlU" plates of quarry operations, etc., and would be well worth obtaining.
•IIIIIIIIIIIIIIIIIII
•
1lIIszdl PrIIIDa J'O'. LId. ACN 08' Ol4 JlJ
This report is available from:
Infonnation Victoria,
356 Collins Street,
Melbourne, Victoria 3000
or
Business Centre
Minerals and Petroleum Division
Department of Natural ResoW'ces and Environment
Ground Floor, 115 Victoria Parade
Fitzroy, Victoria 3065
2
65303 'I
IIIIIIIIIIIIIIIIIIIII
1lM.tt~1I FIIlIlM ",. UtI. AeN 01'014 JIJ
653038LOCATION AND ACCESS
The HRD is located approximately twenty kilometres west-north-west of Scamander.
Access to the area is very good with Hogans Road, an all weather gravel road, traversing
through the middle of the outcrop area. Recent logging activities and road construction by
Foresby Tasmania have created excellent access to virtually all known exposures of the HRD.
GEOLOGY
This section is based on work undertaken in 1992, before most of the recent logging
and roading activities had taken place, and the area was covered in thick vegetation in parts,
which combined with poor outcrop, made field relations difficult to establish. It is likely,
therefore, that fw1:her work will alter the picture drawn at that time.
During 1992, I identified at least fifteen separate bodies ofdiorite ranging from twenty metres
across up to one kilometre across. The small bodies appear to have a pipe-like form, and the
large, irregularly-shaped one kilometre wide body may be composite. A feature of the HRD is
the range in compositions, which include olivine-pyroxene hornblendites, biotite hornblendites,
diorites, quartz diorites, and tonalites. The local geology and location of hand specimen samples
are presented in Figure 1. Those parts of the HRD where the rocks ofgreatest dimension stone
potential (the hornblendites) have been identified in the field are highlighted in Figure 1. Figure
2 shows the location of all samples for which geochemical analyses are presented in Table 1.
The HRD occurs as several discrete bodies within an area of approximately four to five
square kilometres, spatially associated with a septum ofstrongly hornfelsed Mathinna Group
sediments which lies one to two kilometres inside the eastern margin ofthe Haleys New
Counby Pluton, a biotite (± hornblende) granite. The Haleys New Counby Pluton lies at the
centre of the southern end ofthe large exposed part of the Blue Tier Batholith. The HRD is
mostly contained within the Mathinna Group septum but some bodies occur entirely within the
granite. An isolated outcrop of similar diorite also occurs approximately six or seven kilometres
to the north, intruding Mathinna Group sediments.
McClenaghan proposed that the HRD intruded the Mathinna Group rocks before
intrusion of the biotite granite, which has been dated at 396 million years, and the Mathinna
Group rocks and diorite were subsequently transported by the intruding biotite granite as rafts
to their present location. However, a date of364 million years from hornblende separates from
the diorite indicates that the HRD was intruded much later. This date is similar to the intrusion
3
IIIIIIIIIIIIIIIIIIIII
653039
age of the tin granites of north-east Tasmania and recent work on neodymium isotopes has
shown that the HRD appears to have a source more like that of the tin granites than the other
granitic rocks of north-east Tasmania.
PETROLOGY
Chemistry
The HRD exhibits an extreme range in chemical composition and analyses of a range of
samples canied out at the University ofTasmania are presented in Table 1 and sample locations
are shown in Figure 1. In terms of silica content, the composition ranges from -47% SiOz
through to --65% SiOz, or from a gabbro-like composition through to a granodioritic
composition. Rocks with SiOz contents greater than 58% have high Alz0J and low MgO
contents, with MgO and FeO decreasing with increasing silica content. Rocks with contents
lower than 58% tend to have either high MgO (>10%) and low Alz0J « 10%) or low MgO
«10%) with high Alz0J (>15%). One sample fell between the two groups. Modelling ofthe
whole rock geochemical data does not indicate fractionation as a likely mechanism for
generalion of the great range in compositions, the bimodal distribution ofMgO and Alz0J at
lower silica contents more likely to be the result ofmixing between two separate magma types.
Evidence or mixing is also apparent in from textures observed in both hand specimen and thin
section. The presence ofmixing is important as it means that large volwnes ofhomogenous
material are less likely to be found, however textures produced by mixing may give the rock an
attractive look.
Texture
The HRD is not a texturally homogenous body. Based on observations made in 1992,
the diorites, quartz diorites and tonalites, or the intermediate to more felsic (lighter)
compositions, appear to be medium to coarse-grained in the main, and the more mafic (darker)
compositions, the homblendites, are coarse to vel)' coarse-grained. In some samples,
predominantly medium-grained rocks contain bands, blobs or swirls ofcoarser grained material
similar in composition. In some outcrops, there appears to be a crude igneous layering on a ten
or so centimetre scale with contrasting darker and lighter bands. Both these textural features
may impart an attractive look to the stone on a polished surface, however these features may
also provide planes of weaknesses along which failure may occur in a cut slab.
4
IIIIIIIIIIIIIIIIIIII
•
kueU pll/ttRJ P(p. LI4. ACN OIJ tll-l JlJ
653040
Mineralogy
The great range in chemical composition is reflected in the mineralogy of the Hogans
Road diorite. Generally, as the silica content increases, the amphibole content decreases, being
replaced by biotite at more felsic compositions. The most mafic samples have no quartz and
very little plagioclase, and may contain olMne, orthopyroxene and clinopyroxene. The
plagioclase and quartz contents a1Bo increase with increasing silica, giving the rock a lighter
appearance. Electron microprobe analyses shows that the amphibole is predominantly
hornblende with a few analyses ofactinolite in some samples. The composition ofplagioclase is
variable with some samples exhibiting a strong mnation from anorthitic cores to more sodic
rims. Generally, as silica content increases, the plagioclase becomes less calcic. Minor amoWUs
ofK-feldspar is present as microcline in some samples
An important factor in assessing rock for dimension stone potential is the presence of
pyrite and other metallic sulphides. Pynhotite and pyrite are present in small amounts in some
samples, but are not oxidising in the samples examined. A polished section of the most mafic
material made in 1992 shows no staining or deterioration. OlMne my also cause problems
through breakdown, however the olivine present in the HRD hornblendites is generally fresh,
with minor alteration to serpentine. A brief description ofthe hand samples for which thin
sections are available is presented below.
5
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IlMttdl FIIIIM P'tJI. LId. ACN"'014 $13
653041HRI
This sample is a veI)' coarse-grained olivine-pyroxene hornblendite, with large interlocking
Cl)'Stais of hornblende enclosing all other minerals.
hornblende 65-70%- veI)' large anhedral oikocl)'Sts enclosing all other minerals except phlogopite.
olivine 8-100/0- occur as mostly anhedral (some subhedral) fragments in loose clots or stringsup to 10 rnrn long. Fragments contain spinel and have cracks filled withopaques (magnetite), serpentine?
orthopyroxene 5-8%- blocky, anhedral to subhedraI, with inclusions of spinel and globules of olivine.
clinopyroxene 5%- anhedral to subhedral
phlogopite 3-5%- ragged, elongate, occurring between large amphibole phenocl)'Sts
plagioclase 1-2%- anhedral to subhedral, albite twinned
accessory minerals 2-4%apatite - sooty coloured anhedral lumpspynhotite-ilmenite - intergrowthsmagnetite - in cracks in olivinespinelvery minor chalocopyrite
Paragenetic sequence:
olivine, orthopyroxene» clinopyroxene» plagioclase» hornblende, phlogopite
6
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653042HR63
TItis sample is a coarse-grained plagioclase-bearing homblendite.
hornblende 85-90%- seriate textured, subhedral to euhedral, equant to prismatic, 0.2 to 8 mIn; thecores of some larger hornblendes have phlogopite growing along cleavage cracksfonning a "spider web"; the cores of some hornblendes are actinolitic, probablyafter olivine or clinop}Toxene.
plagioclase 5%- subhedral to euhedral prisms; minor to moderate sericitisation ofcores; rnainIyoccurs in gaps between hornblende phenocrysts but some early stronglysericitised plagioclase intergrown with hornblende; andesine compositions (An42-46)
quartz 3-4%- anhedral; occurs between hornblende phenOCl)'Sts
phlogopite 1-2%• occurs along cleavage cracks in large hornblendes, as described above, or asoptically continuous intergrowths in the cores ofhornblendes
rnicrocline 1%- minor anhedral oikocrysts enclosing srna1l euhedral homblendes
clinop}Toxene 1%- srna1l anhedra1 phenocrysts in the cores ofhomblendes
accessory minerals 1%pyrite - in biotiteP}Tfhotiteapatiteallanite - euhedral crystalssphene - anhedral to subhedral
Paragenetic sequence:
clinop}Toxene» early hornblende» plagioclase» late hornblende» rnicrocline, quartz
7
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R-.udl FIIlhM P.I)l. LId. ACN O,J OZ4 JIJ
653043HR50
This sample is a mediwn-grained biotite-hornblende tonalite.
hornblende 3<l-40%- early small subhedral to euhedral phcnoclYSts occur as inclusions within thecorroded cores of plagioclase, but mostly occurs as 2 to 3 mm anhedral tosubhedral phenoclYSts (some euhedral and twinned) in loose clots or strings(gIorneroclYSts) with inclusions of biotite, apatite and pyrite. Large phenoclYStsintergrown with plagioclase cores
plagioclase 25-30"10- occurs as 3 to 4 mm long prismatic phenoctysts with micrographic textures;cores are prismatic or square; corroded or rounded; strongly sericitised;anorthitic (An 90-93); intergrown with large hornblcndesrims are clear or albite twinned with andesine compositions (An 42-47)
quartz 15-20%- anhedral, intergranular
biotite 5-10"10- generally skeletal and ragged, sorne elongate and tabular up to 3 mm long,some occurs within plagioclase cores associated with hornblendegJorneroctySts; some included in plagioclase cores; minor to moderate alterationto phrenite.
accessOty minerals 1%apatite - ablDldant sooty, rOlDlded prismspyriteihnenitezirconsphene
Paragenetic sequence:
biotite, hornblende» plagioclase cores » biotite, plagioclase rims» hornblende» quartz
8
9
Paragenetic sequence:
biotite, plagioclase» lathe-like plagioclase» biotite, hornblende» q~
q~ 2~300A>
- mainly interstitial; some 2-3 mm diameter ocelli with rims containing inclusionsof plagioclase lathes, biotite, and apatite needles
hornblende 1~200A.
- occurs as anhedral phenocrysts in irregular clumps; intergrown with biotite;patchy sub-solidus alteration.
653044
biotite 1~20%
• occurs as ragged growths and g1omerocrysts; as inclusions in plagioclase cores;intergrown with hornblende
accessory minerals 1%magnetitezircon - euhedralapatite - needIe-like
plagioclase 40-500A>- prismatic phenocrysts up to 10 mm long.cores are rounded or corroded; some are strongly zoned; moderately to stronglysericitised; biotite inclusions; variable compositions (An 50-83)rims are generally clear; An 43-51some < 0.1 mm lathes associated with biotite and apatite.
HR25
/lJu8ell Faa- P('P. Lid. IICN OlJ 024 J1J
l1Jis sample is a medium-grained hornblende-biotite tonalite.
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R.lu#eU F.... P(p. LI4. ACN 01$ Ol4'13
653045
HR7
1bis sample is a mediwn grained hornblende-biotite tonalite. No thin section has been cut for
this sample.
10
11
There are two main areas of the mafic homblendites, although remapping the deforested
areas may reveal more. Of these, the northernmost area is the largest and probably would be the
best site for any initial assessment work. In terms of UBeful characteristics which may be of help
in exploration, the homblendites of the HRD are much denser than the surrounding rocks and
are also much more strongly magnetic than the surrounding rock. An interpretation of airborne
magnetics undertaken by Mike Roach for his Ph.D. thesis on the geophysical setting of gold
mineralisation in north-east Tasmania shows a relatively strong magnetic anomaly in the vicinity
of the HRD. Measurement of the magnetic susceptibility of hand specimens from a range of
compositions may reveal sufficient variation to enable mapping by ground magnetometer
swvey. It may therefore be possible to identify the largest occurrences of the homblendites and
eliminate smaller areas which are unlikely to be ofeconomic importance. Alternatively, the
denser mass of the homblendites could also be delineated by conducting a detailed gravity
swvey.
An important limiting factor in any rock proposed for dimension stone is the nature of
jointing. Joint spacing is critical in detennining the size of blocks which can be extracted and the
minimization of wastage. Close-spaced jointing may increase wastage and costs or at worst
render a deposit unsuitable. In Victoria, the Harcourt Granite quarries have been able to remain
profitable on extraction rates of 500-600 m3 per year mainly because of favourable joint
patterns, whereas typical extraction rates at other quarries are in the 1500-2000 m3 per year
range. Because ofthe poor exposure, it is not possible to comment on the joint spacing in the
HRD homblendites. A high degree offine fracturing may also make a stone unsuitable and
while some hand specimen samples appear to be free of fine fractures it remains to assess this
on a larger scale.
It may be possible to assess some of these characteristics by trenching through the
homblendites and cutting samples in-situ. I have been involved with extensive trenching
programs as part ofgold exploration in very hard, hornfelsed rocks in the north-east over the
last year and have found that a small ~7-tonne excavator equipped with a ripper tooth and a
quick release mechanism is very effective in digging trenches into relatively fresh rock.
Eventually, some drilling would be required to assess the depth extent and characteristics of the
hornblendites.
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RJuuU PIIIWa Pt.f. LI4. AeN 013 OZ4 $1J
ASSESSMENT AND EXPLORAnON
G53046
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IlIusdJ FMIIDII Pt}t Ltd. ACN 0'$ Ol4 JIJ
65304 '/FURTIffiR READING
Longman, M.l 1961. An occurrence ofhornblende picrite in north-eastern Tasmania. Tech.
Rep, Dept. Mine. Tas. 5, 209-210.
McQenaghan, M.P. 1984. The petrology, mineralogy and geochemistry ofthe Pyengana and
Gardens granodiorites, the Hogans Road diorite and the dolerite dykes ofthe Blue
Tier Batholith. Mineral Resources Tasmania, Unpublished Report 1948/04
McClenaghan, M.P. 1992. Devonian granitoid rocks in McClenaghan, M.P., Twner, N.J. and
Everard, J.L. Geological atlas 1:50,000 series Sheet 41 (85ISS) St. Helens. Explan.
Rep. Geol. Surv. Tasm.
McClenaghan, MP. and Higgins, N.C. 1993. The age and intrusive relationships of
granitoids ofthe Blue Tier Batholith, north-east Tasmania. Mineral Resources
Tasmania,Unpublished Report, 1993/33.
Roach, MJ. 1994. The regional geophysical setting ofgold mineralisation in north-east
Tasmania, Ph.D. Thesis, University ofTasrnania.
12
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Table 1. Grid c:o-ordlnates and chemical composition of Hogans Road diorite.Bold type Indicates samples for which polished slabs are snpplled.
Sample Easting NoJ1hing SI02 TIm A1203 FeZ03 FeO MnO MgO CaO NsZO 100 nos L.O.I. Total
HRl 586535 5419675 45.90 0.42 6.05 1.86 9.28 0.19 23.08 7.87 0.77 0.61 0.13 1. 78 97. 94HR47 586750 5417640 47.71 0.35 6.39 1.45 7.24 0.16 21.97 9.84 0.80 0.82 0.16 2.26 99.15HR28 586730 5419300 47.77 0.18 20.27 1.24 6.20 0.16 9.22 10.53 1.35 0.85 0.04 237 100 18HR57 586740 5417490 48.90 0.36 7.13 1.39 6.97 0.15 19.86 9.12 0.89 1.07 0.18 3.27 9929HR21 586840 5419350 49.71 0.56 9.79 1.44 7.18 0.16 16.63 8.40 1.37 1.37 0.13 2.45 99.18HR46 586605 5419275 51.05 0.50 9.62 1.55 7.77 0.22 16.02 8.05 0.84 1.38 0.13 2.17 9931HR43 586670 5418420 51.12 0.93 15.33 1.45 7.26 0.17 7.92 8.68 1.65 1.84 0.27 2.21 9883HR50 586640 5419200 51.# 0.95 14.98 1.58 7.92 0.15 6.57 9.37 1.61 1.66 0.39 1. 72 98.34HR53 586690 5417340 52.08 0.44 12.33 1.36 6.79 0.15 10.13 12.50 1.13 0.98 0.08 1.74 99.71HR63 586700 5417#0 52.29 0.40 7.45 1.27 6.34 0.15 15.58 10.96 1.03 1.00 0.19 2.09 98.74HR7 586660 5418410 52.61 1.09 17.37 1.53 7.67 0.17 4.63 8.51 1. 72 2.23 0.23 1.47 99.24HR60 586700 5417430 57.50 0.36 6.08 1.08 5.38 0.15 12.45 12.48 1.22 1.45 0.06 1.57 99.77HR44 586680 5418435 59.00 0.85 16.33 1.17 5.86 0.15 3.58 6.69 2.12 2.11 0.14 1.27 99.28HR51 586835 5419030 60.02 0.71 16.50 1.08 5.41 0.13 3.42 6.46 1.75 2.04 0.14 1.53 9919HR25 587105 5418970 61.35 0.93 15.93 1.02 5.12 0.14 J.38 6.26 1.67 1.81 0.18 1.53 99.33HR17 586960 5418555 63.24 0.63 16.05 0.81 4.06 0.10 3.34 5.41 2.28 225 0.15 1.17 99.50HR66 586260 5417520 63.91 0.71 15.21 0.96 4.82 0.13 2.98 5.10 1.74 2.74 0.16 1.53 9999HR45 586200 5417280 64.07 0.90 15.31 0.98 4.91 0.10 2.03 5.04 1.83 2.28 0.18 1.50 9913HR12 586695 5418515 64.89 0.81 15.00 0.92 4.60 0.11 2.38 5.25 1.64 2.23 0.16 ]]5 99.14
C")c..r.W0Acc
653051Figure 1. Hogans Road diorite. Location of samples forwhich polished slabs are supplied. Scale 1:25,000
North... -+
... ... + .j. t-
... + + of' +,4 I
~ ... ,; + -+ ....,/ .... ...., ..
~ + + ....::.... \. .., ..... ' ..
-+ · ..+ + - · .....
.... .'· ..... ~. ....·-l- .... .' · ..· .
+ ·..... . .'· .~ + ...,
4- ·.t f -++ +
.... +-t + +
.... ~+ .. ~ ++...
+4- ....
+-+ ++ +... ~ + ... -+
1~·..r""___"""1""'+Pi . $ GIlly.
+
B H~D· -+"",,\,+<.o; do""oo.rtf
\l~D. ~....bI..,J;4<s J..,;no.+
ill B;04;~. y.,,;-\...
542()()()()
5419000
5418000
:'0..5416000
·-1 : :. '.~ ',:
~ ~ ~ § ~<""-~ ~ ~ ~ ~
5417000
Scm
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Figure 2. Hogans Road diorite. Locations of samplesfor which major element chemistry is presented inTable 1. Scale 1:25,000
5420000 .. I I
.-!HIll
5419500 f- -~l-tHR~
-llWO
5419000 f- -tHll51-fHll2S -
.
5418500 f- +HR12 +HR17 -+HR7.43.44
5418000 --
-!HIl47
5417500 '- -+HR66 -+HRS7 -+HR63.6O
-llW3-+HR4S
5417000 .. I I
8 8 § 8q; i2 or>c- c-oo 00~ ~or> or>
653052